-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathobserverPattern.java
More file actions
169 lines (129 loc) · 3.69 KB
/
observerPattern.java
File metadata and controls
169 lines (129 loc) · 3.69 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Random;
abstract class Feature {
public String name, unit;
Feature(String name, String unit) {
this.name = name;
this.unit = unit;
}
@Override
public String toString() {
return this.name;
}
abstract String getCurrentValue();
}
class Temperature extends Feature {
Temperature(){
super("Temperature", "Celsius");
}
@Override
String getCurrentValue() {
Random rand = new Random();
Integer val = rand.nextInt(100);
return val.toString() + " " + this.unit;
}
}
class Humidity extends Feature {
Humidity(){
super("Humidity", "Percentage");
}
@Override
String getCurrentValue() {
Random rand = new Random();
Integer val = rand.nextInt(100);
return val.toString() + " " + this.unit;
}
}
class Pressure extends Feature {
Pressure(){
super("Pressure", "Pascal");
}
@Override
String getCurrentValue() {
Random rand = new Random();
Integer val = rand.nextInt(100);
return val.toString() + " " + this.unit;
}
}
abstract class Subject{
ArrayList<Observer> ob_array = new ArrayList<>();
HashMap<String, Feature> features = new HashMap<>();
abstract void addObserver(Observer ob);
abstract void removeObserver(Observer ob);
abstract void notifyObservers();
void addFeature(Feature f) {
features.put(f.name, f);
System.out.printf("Added <%s> to <%s>\n",f,this);
}
void removeFeature(Feature f) {
features.remove(f.name);
System.out.printf("Removed <%s> from <%s>\n",f,this);
}
void removeFeature(String feature_name) {
features.remove(feature_name);
System.out.printf("Removed <%s> from <%s>\n",feature_name,this);
}
public abstract String toString();
}
class WeatherService extends Subject{
WeatherService(){
this.addFeature(new Temperature());
this.addFeature(new Humidity());
this.addFeature(new Pressure());
}
@Override
public void addObserver(Observer ob) {
ob_array.add(ob);
}
@Override
public void removeObserver(Observer ob) {
ob_array.remove(ob);
}
@Override
public void notifyObservers(){
for(Observer ob: ob_array) {
ob.update(this);
}
}
@Override
public String toString() {
return "WeatherService";
}
}
interface Observer{
void update(Subject sub);
}
class GoogleMap implements Observer {
@Override
public void update(Subject sub) {
System.out.println("Update called from " + this);
System.out.printf("Temperature %s\n", sub.features.get("Temperature").getCurrentValue() );
}
public String toString() {
return "Google Map";
}
}
class AccuWeather implements Observer {
@Override
public void update(Subject sub) {
System.out.println("Update called from " + this);
System.out.printf("Temperature %s\n", sub.features.get("Temperature").getCurrentValue() );
System.out.printf("Pressure %s\n", sub.features.get("Pressure").getCurrentValue());
}
public String toString() {
return "AccuWeather";
}
}
public class ObserverPattern {
public static void main(String[] args) {
Subject weather = new WeatherService();
Observer Gmap = new GoogleMap();
Observer accu = new AccuWeather();
weather.addObserver(Gmap);
weather.addObserver(accu);
weather.notifyObservers();
weather.removeObserver(accu);
weather.notifyObservers();
}
}